Electronically controlled automotive air conditioning compressors are well known in the prior art. Typically, prior art electronically controlled compressor systems include an electronic control module (ECM) in communication with various sensors for measuring vehicle interior and exterior environmental conditions, switches for actuating various air conditioning system modes and output ports for relaying output signals to actuate various system components such as vent doors, blower motor, fans, and valves. These electronically controlled compressors require a control strategy to optimize the system requirements. Without a control strategy capable of optimizing the performance of the air conditioning system, there is little justification for electronically controlling the compressor as compared to mechanically controlling the compressor. Generally, electronically controlled compressor systems weigh more, are more expensive, and require additional sensors as compared to their mechanical counterparts.
However, with optimum control of the electronically controlled compressor systems, the inefficiencies of mechanically controlled compressors caused by a sharp reduction in the evaporator temperature (typically around 35 F.) may be avoided. Automotive air conditioning systems having mechanically controlled compressors operate inefficiently (do more work than is required) in the vast majority of operating conditions.
Therefore, what is needed is a new and improved system and method for controlling electronically controlled automotive air conditioning compressors. The new and improved system and method should not run the compressor unnecessarily. Moreover, it should provide more precise control over the pressures disclosed in the respective compressor chambers.